1. Field of the Invention
The present invention relates to a turbine blade to be installed into a female dovetail of a turbine disk of an aircraft engine.
2. Description of the Related Art
The constitution of a typical turbine blade to be installed into a female dovetail of a turbine disk of an aircraft will be described below.
A typical turbine blade includes a blade airfoil as a blade base, one side of the blade airfoil being a convex suction surface and the other side of the blade being a concave pressure surface. A platform is integrally molded on the hub side (at the base end portion) of the blade and recesses are formed respectively on both sides of the platform. A front seal fin protruding forward is formed at the front end of the platform and a rear seal fin protruding backward is formed at the back end of the platform.
A male dovetail is integrally disposed on the hub side (at the base end portion) of the platform, the dovetail has an engagement portion able to engage with a female dovetail of a turbine disk, and the engagement portion is usually formed by grinding, whereby, a jig is used for grinding, and one side of the platform can be engaged against a platform-locating portion of the jig.
The manufacturing process of the typical turbine blade will be described below. The greater part of the turbine blade with the engagement portion remaining unfinished (an unfinished turbine blade) is molded by casting. Next, the unfinished turbine blade is located in the jig so as to make the dovetail axial direction perpendicular to the repulsive force due to work-resistance during grinding, by letting the pressure surface of the blade airfoil be supported with a support portion of the jig. Further, setting of the unfinished turbine blade onto the jig is completed by pressing the pressure surface of the blade airfoil against the location portion by means of a clamp of the jig. Then, the turbine blade is finished by forming the engagement portion along the dovetail axial direction by grinding.